The present invention relates generally to the field of indoor positioning systems, and more particularly to collecting training data for calibration of the indoor positioning system.
Indoor positioning systems (IPS) are solutions to locate objects and/or people within a building (e.g., store, venue, public service building, etc.) or designated area through sensory information collected by a mobile device. Instead of utilizing satellites, IPS solutions rely on different technologies, including distance measurement to nearby anchor nodes (e.g., nodes with known positions, such as wireless access points), magnetic positioning, and dead reckoning. The IPS either actively locates mobile devices and tags or provides ambient location or environmental content for devices to be sensed. Magnetic positioning utilizes a mobile device to measure magnetic disturbances in the Earth's magnetic field. The magnetic disturbances, when mapped, provide a digital representation of a building's floor plan. Dead reckoning is the process of calculating the current position of an individual by using a previously determined position, or a position derived from measuring external reference points, and advancing that position based upon known or estimated speeds over an elapsed time and course.
Wireless indoor positioning systems apply a localization technique used for positioning that is based on measuring the intensity of a received signal strength indicator (RSSI) associated with a wireless access point. The wireless access points (WAPs) are special-purpose communication devices on wireless local area networks (WLANs), consisting of radio transceivers, antennas and device firmware that act as a central transmitter and receiver of wireless radio signals. Additionally, the wireless access points include unique identifiers such as a service set identification (SSID) and a media access control address (MAC address) that aid in geo-location. The wireless indoor positioning system accesses a database that correlates mobile device GPS location data with the MAC addresses of the access points thus providing a geo-location of the associated wireless access point. The received signal strength indicator (RSSI) is a measurement of power present in a received radio signal. Signal strength refers to the magnitude of an electrical field (e.g., signal) at a reference point that is a distance from the transmitting antenna. Calibration of devices (e.g., indoor positioning systems) occur based on a comparison between RSSI measurements, one of a known magnitude (e.g., made or set), and another RSSI measurement associated with a received radio signal.